GURPs didn't let you design your gear they just didn't provide any of it in the base book. They then released all the "Equipment" books which you'd then go out and purchase so you could gear up your characters. As an aside, GURPs vehicles did allow you to design your own vehicles but you'd better have a spreadsheet and a math degree if you wanted to make it work.

HERO system actually has all the rules for designing gear/vehicles/powers/abilities right in the base book. Technically you could go out and buy just that and you'd never have to invest in another book because the rules for Everything are right there in the base book.

Hero system has released a number of supplements with pre-designed equipment/abilities in them but they often try and cover very wide ranges which limits how effective they are. The vehicles book for example covers everything from your hollowed out log canoe to space faring capital ships. This means that while there's a good chance there's something in there you can use it's going to be pretty sparse and you'll still end up filling in the areas that got overlooked.

Like I said, I love the system but I just can't find any practical way of using it.

TBO

The way we always used it, when we did, was as a supliment.
If we couldn't find what we wanted, we cracked open GURP's and made it, converted it, or picked it out of the book. Which ever option suited us the best.
The other thing was that we played a heavy game of pick and choose your rules with GURP's, only applying things that we thought were needed and completely disregarding the rest until it was needed.

But yes, in general...GURP's is too general. But if you have your own engine that you built and you need stuff to flesh it out here and there...nothing is better